Nokea
The nurse is reviewing the physiological factors that affect a patients cardiovascular health and tissue oxygenation. What is the systemic arteriovenous oxygen difference?
- A. The average amount of oxygen removed by each organ in the body
- B. The amount of oxygen removed from the blood by the heart
- C. The amount of oxygen returning to the lungs via the pulmonary artery
- D. The amount of oxygen in aortic blood minus the amount of oxygen in the vena caval blood
Correct Answer: D
Rationale: The average amount of oxygen removed collectively by all of the body tissues is about 25%. This means that the blood in the vena cava contains about 25% less oxygen than aortic blood. This is known as the systemic arteriovenous oxygen difference. The other answers do not apply.
You may also like to solve these questions
A nurse in the rehabilitation unit is caring for an older adult patient who is in cardiac rehabilitation following an MI. The nurses plan of care calls for the patient to walk for 10 minutes 3 times a day. The patient questions the relationship between walking and heart function. How should the nurse best reply?
- A. The arteries in your legs constrict when you walk and allow the blood to move faster and with more pressure on the tissue.
- B. Walking increases your heart rate and blood pressure. Therefore your heart is under less stress.
- C. Walking helps your heart adjust to your new arteries and helps build your self-esteem.
- D. When you walk, the muscles in your legs contract and pump the blood in your veins back toward your heart, which allows more blood to return to your heart.
Correct Answer: D
Rationale: Veins, unlike arteries, are equipped with valves that allow blood to move against the force of gravity. The legs have one-way bicuspid valves that prevent blood from seeping backward as it moves forward by the muscles in our legs pressing on the veins as we walk and increasing venous return. Leg arteries do constrict when walking, which allows the blood to move faster and with more pressure on the tissue, but the greater concern is increasing the flow of venous blood to the heart. Walking increases, not decreases, the heart pumping ability, which increases heart rate and blood pressure and the hearts ability to manage stress. Walking does help the heart adjust to new arteries and may enhance self-esteem, but the patient had an MIthere are no new arteries.
The nurse is caring for a patient with a large venous leg ulcer. What intervention should the nurse implement to promote healing and prevent infection?
- A. Provide a high-calorie, high-protein diet.
- B. Apply a clean occlusive dressing once daily and whenever soiled.
- C. Irrigate the wound with hydrogen peroxide once daily.
- D. Apply an antibiotic ointment on the surrounding skin with each dressing change.
Correct Answer: A
Rationale: Wound healing is highly dependent on adequate nutrition. The diet should be sufficiently high in calories and protein. Antibiotic ointments are not normally used on the skin surrounding a leg ulcer and occlusive dressings can exacerbate impaired blood flow. Hydrogen peroxide is not normally used because it can damage granulation tissue.
A nurse in a long-term care facility is caring for an 83-year-old woman who has a history of HF and peripheral arterial disease (PAD). At present the patient is unable to stand or ambulate. The nurse should implement measures to prevent what complication?
- A. Aoritis
- B. Deep vein thrombosis
- C. Thoracic aortic aneurysm
- D. Raynauds disease
Correct Answer: B
Rationale: Although the exact cause of venous thrombosis remains unclear, three factors, known as Virchows triad, are believed to play a significant role in its development: stasis of blood (venous stasis), vessel wall injury, and altered blood coagulation. In this womans case, she has venous stasis from immobility, vessel wall injury from PAD, and altered blood coagulation from HF. The cause of aoritis is unknown, but it has no direct connection to HF, PAD, or mobility issues. The greatest risk factors for thoracic aortic aneurysm are atherosclerosis and hypertension; there is no direct connection to HF, PAD, or mobility issues. Raynauds disease is a disorder that involves spasms of blood vessels and, again, no direct connection to HF, PAD, or mobility issues.
While assessing a patient the nurse notes that the patients ankle-brachial index (ABI) of the right leg is 0.40 . How should the nurse best respond to this assessment finding?
- A. Assess the patients use of over-the-counter dietary supplements.
- B. Implement interventions relevant to arterial narrowing.
- C. Encourage the patient to increase intake of foods high in vitamin K.
- D. Adjust the patients activity level to accommodate decreased coronary output.
Correct Answer: B
Rationale: ABI is used to assess the degree of stenosis of peripheral arteries. An ABI of less than 1.0 indicates possible claudication of the peripheral arteries. It does not indicate inadequate coronary output. There is no direct indication for changes in vitamin K intake and OTC medications are not likely causative.
A patient comes to the walk-in clinic with complaints of pain in his foot following stepping on a roofing nail 4 days ago. The patient has a visible red streak running up his foot and ankle. What health problem should the nurse suspect?
- A. Cellulitis
- B. Local inflammation
- C. Elephantiasis
- D. Lymphangitis
Correct Answer: D
Rationale: Lymphangitis is an acute inflammation of the lymphatic channels. It arises most commonly from a focus of infection in an extremity. Usually, the infectious organism is hemolytic streptococcus. The characteristic red streaks that extend up the arm or the leg from an infected wound outline the course of the lymphatic vessels as they drain. Cellulitis is caused by bacteria, which cause a generalized edema in the subcutaneous tissues surrounding the affected area. Local inflammation would not present with red streaks in the lymphatic channels. Elephantiasis is transmitted by mosquitoes that carry parasitic worm larvae; the parasites obstruct the lymphatic channels and results in gross enlargement of the limbs.